Shock-absorbing motion-retarding pallet



2 Sheets-Sheet 1 Jan. 28, 1964 J. KlRscH ETAL sHocK-ABsoRBING MonoN-RETARDING PALLET Filed Jan. so, 1962 ATTORNEYS Jan. 28, 1964 J. KlRscH ETAL sHocx-ABSORBING MoTmN-RETARDING PALLET 2 sheets-sheet 2 Filed Jan. 50, 1962 FIG? F |66 INVENTORS JERRY KIRSOH EMIL J. TITO ATTORNEYS Unite States Patent Gllice 3,119,357 Patented .lam 28, 1mb@ 3,119,357 SHCIQABSRBING MGTXN-RETARDHNG BALLET Jerry Kirsch, 3946 Bishop Road, and Emil l'. Tito, 3915 lishop Road, both of Detroit 24', Mich. Filed ian. 3l), 1952, Ser. No. 169,'7l4i 6 (Cl. Hi8-51) This invention relates to pallets, such as are used to support boxes, bins or yother loads while being transported and in particular, to pallets suitable for vehicle mounting and transportation.

One object of this invention is to provide a shockabsorbing motion-retarding pallet which may be mounted upon or in a cargo vehicle, such as a railway flat car, freight oar or baggage car, highway truck, trailer, semi* trailer, cargo aircraft or ship, and which permits the speed of the load carried thereby to be subjected to a controlled retarded rate of deceleration or acceleration upon the occurrence of a more rapid deceleration or acceleration of the vehicle which might otherwise cause dam-age to the cargo by la rapid deceleration or acceleration of the vehicle itself.

Another object is to provide a shockebsorbing motionretarding pallet oi the foregoing character which is adapted to be conveyed from place by a conventional forklift truck, the forks of which are inserted through slots `in the side walls of the stationary portion of the palle-t.

Another object is to provide a shock-absorbing motionretarding pallet of the foregoing character wherein the rate of deceleration or acceleration of the movable loadsupporting part of the pallet by the action of a hydropneumatic retarding device is caused to be reduced to a controlled rate well below lthe rate of deceleration or acceleration of the relatively stationary portion of the pallet mounted on the vehicle.

Another object is to provide a shock-absorbing motionregarding pallet of the foregoing character wherein the deceleration and acceleration `of the load may be maintained bellow .a predetermined rate considered to be damaging to the particular cargo or other load, the controlled deceleration or acceleration being effected by means of a load-supporting slide coupled to a relatively stationary support through a hydropneumatic reciprocatory motor and operative in either `of the opposite directions of travel of the vehicle.

Other objects and advantages of the invention will become apparent during the course `of the following description of the accompanying drawings, wherein:

IlGUlE l is la perspective view of a shockebsorbing mo=tion-retarding pallet according to one form of the invention, as mounted upon 'the bed or chassis of a vehicle shown in fragmentary form;

FlGURE 2 is a central vertical section through the pallet shown in FIGURE l, taken yalong lthe line 2--2 therein, with the hydropneumatic `shock-absorbing cushioning cylinder `shown in side elevation;

FIGURE 3 is `an enlarged top plan view, mainly in central horizontal section, `of the shoe. -absorbing hydropneumatic motor or cylinder shown in FIGURES l and 2, taken along `the line 3 3 in FIGURE 2 with the parts in their fully-extended positions;

FlGURE 4 is a reduced-size top plan View of the shoes-absorbing pallet shown in FIGURE l;

FIGURE 5 is a cross-section taken along the line 5 5 in FIGURE 4;

FIGURE 6 is a central vertical longitudinal section similar to FIGURE 2, but showing the relative positions of the moving parts during controlled retarded deceleration of the pallet slide in the course of forward travel deceleration of the vehicle; and

FIGURE 7 is a view similar to FGURE 6 but showing the relative positions o-f the moving parts during controlledA retarded deceleration of the vehicle in the course of rearward travel thereof.

Refer-rmg 'to the drawing lin detail, FIGURE l shows diagrammatically the oor 10 of a vehicle, generally designated 12, having side members 14 provided with conventional connections 16 for so-oalled chain binders 18 by which is anchored a shock-absorbing ntotion-retarding pallet, generally designated 2li', according to one form off the present invention. The vehicle l2 may consist of a r-ajlnoad at car, reight car, baggage car or the like, or it may be a truck, semiatmailer, cargo aircraft or ships deck, as the case may be.

The pallet 2li consists generally of a relatively stationary' frame structure or base structure 22 supporting a relatively-slidable load-carrying structure, generally designated 24, connected thereto through a hydro-pneumatic shocl 1-absorbing controlled motion-retarding reciprocatory motor, generally 'designated 26, described more fully below. The relatively stationary structure 22 is so called because it does not move relatively t-o the lloor or bed lll: during operation, leven though the lvehicle having the floor or bed l@ does move relatively to the road, road bed, ground for surface of the sea, las the case may be, whereas the slidable loadcarrying structure 24 does so move relatively to the vehicle floor lll.

FDhe stationary frame structure or base structure 22 is of approximately rectangular shape and is composed of channel side members Z3 interconnected by channel cross members or end members Sil. Extending between the end members Ell 'are guideways or guide bars 32 serving to slidably support the movable load-carrying structure 24. For simplicity' and clarity of disclosure, the load-carrying structure M has been shown as supported upon the guideways 32 by plain bearings. lt will be understood, however, that the structure 24 is equally well adapted to be supported on anti-friction rollers in iorder to further reduce the friction and to substantially eliminate jolts incidental Ito the retarding action of such friction. The relatively-slidable load-carrying structure 24 is retained in position by retaining bars or gibs 33 located near the stationary frame side members 28 and extending between che opposite end members Btl.

One of the side members 23 land one of the end members 3d is provided with a pair of slots '34 or 36 respectively lior the insertion of the parallel horizontal forks of a conventional forklift truck (not shown). By this means, the shocloabsorbing motion-retarding pallet 291 with its load L may be hauled from place to place and deposited on the floor lll Iof lthe vehicle l2 and anchored in position by the chain i8 attached to the connection 16 on the side member le of the floor or bed 10| of the vehicle l2. The opposite end of the chain 1S is connected as at 38 (FIGURE 1) to the relatively stationary frame structure 22.

The relatively-movable load-carrying structure 24 rests upon and slid-ably engages the guides members or guideway 32 and consists of a rectangular plate 40 off steel or other suitable material. The box or other cargo load L rests upon the slide plate 4t? and is secured thereto. lt will also be understood that the plate 4@ may constitute the bottom of a box-shaped container in which parcels or other arti-cles may be placed in order to protect them from the weather during transit. The guide bars 32 me secu-red to and rest upon the upper flanges 42 (FIGURE 5) of vertical channel members 44, the lower flanges 46 of which rest upon and are secured to a bottom plate itl welded or otherwise secured to the longitudinal members 2,3 `and cross members 35i of the station-ary frame structure 2.2.

Welded or otherwise secur to the bottom plate 48 of the relatively stationary frame structure 22 are lonarrasa? gitudinallly-spaced pairs of upstanding abutment members 9 and Si) (FIGURES 3, 5, 6 and 7), the individual abutment members 49 or Sil of which are spaced laterally apart from one another (HGURE 3). Welded or otherwise secured to the top plate it? of the relatively movable cargo-carrying structure are two longitudinally-spaced depending or downwardly-extending thrust plates 5l and 52 extending into the spaces between the upstanding stationary abutment members i9 and Sti` so as to slide freely between them. The opstanding stationary abutment members 49 and 56 and the thrust plates 5l and 52 have spherical concave recesses or seats 56 and 53 respectively for receiving the correspondingly-curved spherical con- Vex end surfaces 6@ and 62 of the cylinder head 64 and piston rod end 66 of the hydro-pneumatic reciprocatory motor 26 (FIGURES 2, 6 ,and 7) so as to minimize any adverse effects of misalignment arising either during assembly or operation by providing a relatively sliding sel-falignin'g or pivoting connection therebetween.

The cylinder head 64 is connected to and closes one end of a cylinder 66 ('FXGURE 3), whereas the piston rod end 66 forms the forward end of a hollow piston rod 761 connected to a hollow piston head 7l reciprocably mounted within the cylinder bore 72 of the cylinder 68. The cylinder 6d near its open end 74 through which the hollow piston rod itl passes is provided with a vent port 76, and -slidably engages a guide block 77 on the bottom plate 48.

The hollow piston rod 77 is provided with a longitudinal bore `73 in which is reciprocably mounted a free or floating piston Sil dividing the piston rod boire 78 into a pneumatic chamber 82 lled with a suitable compressed gas, such as compressed nitrogen, and an intermediate or middle hydraulic chamber 34 adapted to be filled with and temporarily at least partially emptied, during operation, of a suitable hydraulic Working iluid, such as oil. The end orf the cylinder bore 72 contains a main hydraulic chamber S6, also adapted to contain the same hydraulic workin-g fluid, such as oil. The piston rod end 66 is provided with a passageway 87 closed by a pneumatic charging fitting 3S containing a valve (not shown) similar to that of a pneumatic tire-lling val-'ve and provided for the purpose of charging the pneumatic chamber with fthe compressed gas just mentioned.

The hollow piston rod bore 78 at the end opposite the piston rod end 66 is provided with a counterbore 90 4into Which is threaded or otherwise secured the correspondingly -threaded flange 92 of a ow control valve, genorally designated 94. The ilow control valve 9d contains a spring-pressed tubular reciprocatory valve member (not shown) which opens and closes wall ports in the valve casing 96 between the anges 92 and 9S thereof. The `flange 92 has longitudinal 4ports (not shown) connecting the space between the flanges 92 and 9S through the main hydraulic chamber S6.

The flow control valve 94 is of any suitable type responsive to 4the attainment of a predetermined pressure in the intermediate hydraulic chamber 84 to open and discharge hydraulic uid therefrom into the main hydraulic chamber 86. The llow control valve 94 contains a small through passageway (not shown) permitting small quantities of hydraulic fluid to ilow in opposite directions between the chambers 84 and 86. Such a suitable flow control valve 9dis disclosed `and claimed in combination With the hydro-pneumatic cushioning or impact shock absorbing cylinder or motor 26 in the copending Kirsch application, Serial No. 72,476 tiled November 29, 1960, for Constant Speed Reoiprocable Hydro- Pneurnatic Motor, now U.S. Patent 3,079,897 of March 6, 1963, and is shown particularly in FEGURE 3 thereof.

In the operation of the shock-absorbing motion-retarding pallet of the present invention, let `it be assumed that a load L, such as a box, has been mounted on and secured to the slide plate 46 (FIGURE 2) of the pallet 2l) Willis? the @latir/ely stationary frame 22 thereof is resting upon the floor Iof a Warehouse or other approximately horizontal surface Ifrom, which is it intended to be moved to the cargo-carrying vehicle l2. Let it also be assumed that the hydro-pneumatic reciprocaitory cushioning motor 26 has been charged with hydraulic and pneumatic lluid of the type described above, with thehydraulic uid occupying the chambers 3d and 36 and the pneumatic nid iin the charnber 32 (FGURE 3).

The fork lift truck operator then moves hisV truck up to the pallet 2li and inserts the fork. thereof either through the side slot 34 or end slots 36 thereof, which 4is more convient, operates the lifting mechanism to cause the fork to move upward and carry with it the pallet Ztl and its cargo load L and then operates the forli lift truck to carry this burden up to and upon the floor or bed l@ of the vehicle l2, depositing it in the desired location. The operator then anchors the pallet 2d, with its cargo load L, to the vehicle floor or bed `lil by means of the chains i8 between the connections 3S and lo". The Vehicle l2 is then ready lfor travel, which for the purpose of the present example will be assumed to be from left lto right in the direction of travel indicated by the arrow at the upper right-hand side of FIGURE l.

Let it be assumed that during the `travel of the vehicle l2, the opera-tor of the vehicle V12 has been forced to apply the brakes thereof suddenly, causing rapid deceleration of the vehicle l2. The cargo load L on each pallet 2Q, of which there may 'be many secu-red to the vehicle door or bed lll, by reason of its acquired momentum, continues to travel in a forward direction lfrom left to right, moving the ,movable cargo-carrying structure 24 from left to right .in FEGURE l. As this occurs, the hollow piston rod 7) .connected to the top plate 46' of the relatively movable cargo-carrying structure 24 by the piston rod end 66 and thrust plate Sl is forced toward the Iforward end of the bed or tloor lll of the vehicle 12 as the thrust plate Si moves outward to the right from be Ween the stationary fabutments 49. This action forces the flow control Valve 94 of the cushioning reciprocatory motor 26 to open and thereby to permit hydraulic fluid to flow at a controlled rate and constant Aspeed from the main hydraulic chamber S6 into the intermediate hydraulic chamber S4 where it in turn forces the free piston 80 to move toward the piston rod end 66, further compressing the gas in the pneumatic chamber 82.

This action produces a controlled retarded deceleration of the movable pallet cargo-carrying structure 24 relatively to the more rapidly `decelerating relatively stationary frame structure 22 which is anchored to the vehicle floor or bed di). In consequence, the reduced eceleration thereby produced prevents damage which might otherwise occur to the cargo or load L .if the latter were iixedly secured to the vehicle bed or floor lil. Meanwhile, if any weaving or misalignment of the components of the cushioning reciprocatory motor 26 occur, the rounded ends 66 and 62 of the cylinder head 64 and piston rod end 66 self-align themselves in their respective spherically-curved concave recesses 56 and 58.

When the deceleration of the cargo vehicle l2 has ceased, the pressure of the pneumatic i'luid thereby compressed in the pneumatic ,chamber S2 of the cushioning cylinder or motor 26 by the movement of the free or floating piston therein causes the hollow piston rod '70 `to move away from its respective cylinder 68. This action pushes the movable load-carrying structure 24 of the pallet 26 to the lef-t (FIGURE l) toward its original position relatively to the relatively stationary frame structure 22 of the pallet 20, thus returning the load L to its original position without damage.

'.[he shock-absorbing pallet Ztl also serves to protect the load or cargo L against damage due to rapid acceleration or deceleration during backing as Well as during forward travel. The cushioning cylinder or motor 26 under these circumstances provides a controlled deceleration for the cargo load L when the latter and its supporting frame 24 move rearwardly in response to the rapid deceleration or halting of the vehicle 12 in a rearward direction, in a manner similar to that described :above for the forward deceleration, except that the thrust plate 52 now moves outward to the left from between its abutments 50, pushing the .cylinder 68 toward the piston head 71 as the piston rod end 66 is held stationary against the abutments 49.

What we yclaim is:

1. A shock-absorbing motion-retarding pallet for use on a vehicle, comprising a generally horizontal bas'e structure adapted to be secured to the vehicle and having longitudinally-disposed guide means thereon,

a generally horizontal load-carrying structure slidably mounted on said guide means for sliding motion longitudinally of said base structure in the direction of travel of the vehicle,

and a iiuid pressure motion-retarding reciprocatory motor disposed between said structures and having a .cylinder element engaging one of said structures and `a piston element reciprocably mounted in said cylinder element engaging the other of said structures,

said motor including means responsive to the attainment of a predetermined pressure Within said motor for controlledly releasing pressure uid from one of said elements into the other element in consequence of relative motion between said elements.

2. A shock-absorbing motion-retarding pallet, according to claim 1,

wherein said motor piston has a hollow piston rod, wherein an auxiliary piston head is mounted for reciprocation within said piston rod, and wherein pneumatic -lluid is disposed on one side of said auxiliary piston head and hydraulic uid on the other side thereof. 3. A shock-absorbing motion-retarding pallet, according to claim 1,

wherein said base structure has an abutment thereon engaging one of said elements,

wherein said load-carrying structure has a thrust member projecting therefrom into engagement with the other element wherein said load-carrying structure includes a load-carrying plate, and

5 wherein said thrust member is secured to and `depend from said plate.

4. A shock-absorbing motion-retarding pallet, according to claim l,

'wherein said base structure has a pair of longitudinally-spaced abutments thereon,

wherein said motor is disposed between said abutments with its elements contactingly eng-aging said elements,

wherein said load-carrying structure has a pair of longitudinally-spaced thrust members projecting therefrom into adjacency to said abutmenfts and into contacting engagement with said elements, wherein said load-.carrying structure includes a load-carrying plate, and wherein said thrust members are secured in longitudinally-spaced relationship to said plate and depend there- -from into adjacency to their respective abutments.

5. A shock-absorbing motion-retarding pallet, according to claim 1, wherein said pressure-Huid releasing means releases pressure vfluid at an approximately constant rate of Huid ow.

6. A shock-absorbing motion-re-tarding pallet, according to claim 1, wherein said pressure-uid releasing means includes a hollow valve casing having wall ports therein and a spring-pressed reciprocatory valve member reciprocably mounted in said valve casing in opening and closing relationship with said wall ports.

i References Cited in the le of this patent UNITED STATES PATENTS 

1. A SHOCK-ABSORBING MOTION-RETARDING PALLET FOR USE ON A VEHICLE, COMPRISING A GENERALLY HORIZONTAL BASE STRUCTURE ADAPTED TO BE SECURED TO THE VEHICLE AND HAVING LONGITUDINALLY-DISPOSED GUIDE MEANS THEREON, A GENERALLY HORIZONTAL LOAD-CARRYING STRUCTURE SLIDABLY MOUNTED ON SAID GUIDE MEANS FOR SLIDING MOTION LONGITUDINALLY OF SAID BASE STRUCTURE IN THE DIRECTION OF TRAVEL OF THE VEHICLE, AND A FLUID PRESSURE MOTION-RETARDING RECIPROCATORY MOTOR DISPOSED BETWEEN SAID STRUCTURES AND HAVING A CYLINDER ELEMENT ENGAGING ONE OF SAID STRUCTURES AND A PISTON ELEMENT RECIPROCABLY MOUNTED IN SAID CYLINDER ELEMENT ENGAGING THE OTHER OF SAID STRUCTURES, SAID MOTOR INCLUDING MEANS RESPONSIVE TO THE ATTAINMENT OF A PREDETERMINED PRESSURE WITHIN SAID MOTOR FOR CONTROLLEDLY RELEASING PRESSURE FLUID FROM ONE OF SAID ELEMENTS INTO THE OTHER ELEMENT IN CONSEQUENCE OF RELATIVE MOTION BETWEEN SAID ELEMENTS. 